Adjustable crank



2 sneets-sheet 1.

(No Model.)

s. NPOND. ADJUSTABLE GRANK.

No. 421,969. Patented Feb.25, 1890.

UNITED STATES IPATENT OFFICE.

SAMUEL N. POND, OF NEWV HAVEN, CONNECTICUT, ASSIGNOR TO JOSEPH H. BLACKVOOD, OF IVASHINGTON, DISTRICT OE COLUMBIA ADJ USTB LE CRAN K. e

SPECIFICATION forming part of Letters Patent No. 421,969, dated February 25, 1890.

Application filed December 20, 1889. Serial No. 334,372. (No model.)

T0 all whom t may concern.-

Beit known thatl, SAMUEL N. POND, acitizen of the United States, residing at New Haven, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Adjustable Cranks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to adjustable cranks for engines or other machines, being more particularly designed for application to velocipedes, and has for its object to effect the easy throw of the wrist-pin up and down the throwarm without stopping the machine, and in the latter application to effect the easy throw of the pedal up and down the crank-arm without 'the necessity of dismounting. A bicyclist in coming to a long rising grade would find it a great advantage if, without being obliged to stop and dismount, he could effect the throw of his pedal an inch or so out on the crankarm, whereby less exertion would be required to overcome the grade; and, conversely, on a level or downgrade, where increased speed is the desideratum, a corresponding shortening of the crank-arm would be advantageous. I accomplish these objects in a simplev and effective manner by the device illustrated in the accompanying' drawings, in which-- Figure 1 is a view of my device applied to the driving-wheel of a bicycle of the wellknown verticalfork type. Fig. 2 is a detail of the pedal attachment. Fig. 3 is a detail of the sliding collar or plate which operates on the vertical fork. Figs. a and 5 are modifications of my crank-arm and pedal.

A represents the crank-arm of a bicycle.

B is a section of the vertical fork, and C is 'a plate or collar designed to slide vertically on the said fork.

The crank-arm A is slotted, as shown, and at one end thereof is provided with a cappiece a, secured to the two forks of the crankarm by screws ZJ b, as shown, or by any other suitable means. The object of this cap-piece a is to brace and strengthen the slotted crankarm and to provide a bearing c for the screw rod or bar D. This rod or bar D is passed longitudinally through the longitudinal eenter of the crank-arm and extends vits entire length. It is threaded part of its length from one end to the gear-wheel c, as shown, and has a bearing at c and a long bearing through the diametrical center of the solid head of the crank-arm, as shown by dotted lines in Fig-.1. e At one end and at a suitable intermediate point are gear-wheels c and e en said rod D as their axis, not rotating thereon,but having a fixed bearing, so that they cannot be rotated without rotating the rod D.

The pedal which operates on the slotted throw-arm A is of the form .shown in detail in Eig. 2. Through the end which is designed to slide on the slotted crank-arm is made a hole f, internally threaded to engage with the threaded portion of rod D. Above and below said hole are formed grooves to engage with the two forks of the crank-arm, the bottom of the grooves bearing on theinterior faces of the forks and the shoulders g ghugging the sides of the forks, but not s o tightly las not tol slide easily thereon when well lubricated. lt is thus obvious that, while the screwrod prevents a straining or loosening of the pedal lengthwise of the crank-arm, the bearing of the forks in the grooves on the pedal, as above described, prevents a similar defect erosswise of the arm, and the pedal is as rmly and securely fixed on the crank-arm as if held by clamps and bolts and nuts.

InFigs. e and 5 I have shown a modified form of my device. The crank or throw arm, instead of being slotted, is channeled, as shown in Eig. i, and a eorrespondingly-shaped pedal or wrist-pin (shown in Fig. 5) operates thereupon by engagement with a longitudinal screw rod or bar in the same manner as hereinbefere described.

The crank or throw arm A, constructed and provided as hereinabove described, is shown iixed in the shaft of the driving-wheel in the usual, manner, it of course being necessary to form-a small hole in the said shaft to permit the passage through the same of the rod or bar D.

IOO

C, as aforesaid, is a collar designed to slide on some suitable part of the stationary framework of the machine, and in the case of a bicycle on the vertical fork, being operated signed to engage with the wheels e and e,

respectively, and formed at such position thereon that when the collar is at its highest position, as shown in Fig. 1, wheel e will enwith rack z'. "Vhen the collar is at an intermediate position, neither of the wheels will be in engagement, and when the collar is at its lowest position wheel e. will engage with rack fi. The upward travel of the collar is limited by the shaft of the drivingwlieel and the downward travel is limited by two stops 7s 7s on the franie.

The manner in which my device may be operated when applied to a velocipede is as follows: lVlien the rider comes to a hill and desires to lengthen the crank-arm of his inaoliine, he simply raises the collar C by means of the lever extending` to his liaiidle-bar, which places rack t' in a position toengage wheel e at each revolution of the crank, thus e rotating screw-rod D, and thereby throwing pedal .E farther out. on the arm. Vhen the crank-arm has thus been lengtlieiied sufficiently, the collar is permitted to drop to its intermediate position and the pedal remains in its new position. Similarly when a level or downgrade confronts the rider and speed is his object., by depressing the collar by means of the saine lever, wheel e is thrown into engagement with rack il', the screw-rod is rotated in the opposite direction from formerly, and the pedal is thus thrown nearer the center of revolution and the craiik-arin is shortened, thus permitting more rapid revolution of the sain e, and consequently increased speed.

In the construction of my device I do not limit myself to the exact fornis shown in the drawings or hereinabove described. Any engagement of parts whereby the pedal or wristpin is thrown back and forth on the throwarm by means of a screw rod or bar passing through or parallel to said tlirow-ariii and rotated by gearing fixed on said screw-rod will be within iiiy invention. The gearing may be toothed, frictionahor of any suitable form. Neither do I limit the application of my device to velocipedes alone; but it may be applied to any machine wherein a quick easy adjustment of the length of the lever-arin'is desired. In such application wherein power is applied to a crank or throw ai'in attached to, the ,shaft of a driving-wheel I construct the throw-arm on the saine principle and the saine `general plan as that shown in Fig. l, and

operate the wrist-piii on said throw-arm by a longitudinal threaded rod or bar passing through said throw-arm, said rod or bar being operated by engagement with a rack attached to some stationary part of the frame-work of the machine. a

Having thus described my inveiitioii,what I claim, and desire to secure by Letters Patent, is-

l. A crank for velocipedes and other purposes, comprising a head rigidly connected to the shaft to be turned, a throw-arm projecting from and rigidly fast upon said head and having a bearing adapted for adjustment of a crank-pin thereupon, a crank-pin formed to have adjustment upon said bearing,'and a holding rod or bar in engagement with the crank-pin and throw-arm, whereby the radial distance of said crank-pin from the center may be varied, substantially as described.

2. A crank for velocipedes and other purposes, comprising a head rigidly connected to the shaft to be turned, a throw-arm projecting from and rigidly fast upon said head and having a longitudinal bearing adapted for adjustinent of the crank-piii thereon, a crank pin formed to have adjustment ing, and a holding-rod arrang o ngitudinally upon the throw-arm and engaging with the crank-pin, whereby the radial distance of said crank-pin from the center may be varied, substantially as described. l

3. A crank for velocipedes and other purposes, comprising a head rigidly connected to the shaft to be turned, aslotted or .channeled throw-arm projecting from and rigidly fast upon said head, and a cap on the end of said throw-arm, a screnvthreaded holding rod or bar having one bearing in said cap and another in the head of said throw-arin, and an iiiteriially-threaded craiik-pin engaging with said throw-arm and screw-threaded rod, substantially as described.

4. In a crank for velocipedes and other purn poses, the combination, with a throw-arm, of a crank-pin held in a variable relation to said tlirowarm, a holding rod or bai' engaging with said arm and crank-pin, ainovable plate upon the frame-work engaging faces upon said holdin grod and said movable plate, and a rodextending toward the hand of the operator, whereby the latter is enabled to vary the radiall distance of the cran r-pin from thecenter without stopping the machine, substantially as described.

5. The combination, with a throw-arm havn ing a slot, channel, or bearing therein, of a crankepin formed to engage said slot,'clian nel, or bearing, and a holding rod or bar ar- IOO IIO

ranged in a parallel relation to said throw` arm and in changeable engagement with said pin, substantially as described.

6. The combination, with the frame, of ai plate movable by the hand of the operator, said plate having an engaging-face for engagement with adjusting devices upon the throw-arm for changing the radial distance back and forth on said throw-arm by the roof the "orankpin, substantially as described. tation of said screw-rod, substantially as de-l 7. In a crank for velooipedes and other purscribed. poses, the combination, with a longitudinal In testinionywheieofl affix my signaturein 5 screw-threaded rod having bearings Within presence of two Witnesses.

the throW- arm, of gearing fixed on and Y adapted to rotate said rod, adjustable gear- SAMUEL N. POND. ing on the stationary frame-Work ofthe ma- Witnesses: chine adapted to engage the gearing upon the HENRY E. COOPER,

1o rod, and a Wrist-pin adapted to be thrown ALBERT B. BLACKWOOD. 

